Abstract

Some rare malignant diseases exhibit clinical features and bone marrow aspirate morphology similar to that of acute leukemia. For instance, rhabdomyosarcoma, neuroblastoma, medulloblastoma, anaplastic oligodendroglioma, small cell carcinoma, Ewing’s sarcoma and neuroendocrine tumors have been reported to display an acute leukemia-like morphology in bone marrow aspirates after metastasizing to the bone marrow. Rhabdomyosarcoma (RMS), a malignant tumour of mesenchymal origin which can occur at various sites in the body, is one of the most common soft tissue sarcomas in both children and adolescents, but is rare in adults with a prevalence of less than 1 %. Bone marrow metastases associated with this condition may be readily confused with acute leukemia or lymphoma. Diagnostic confirmation requires immunohistochemical and flowcytometric examinations. In patients with positive CD56 and negative CD45, rhabdomyosarcoma should be included in the differential diagnosis. Here, we report an unusual case of RMS confined to the bone marrow in an older adult.

Key words: Rhabdomyosarcoma, Burkitt’s lymphoma, bone marrow, CD56(+), CD45(-)